This invention relates to rug cleaning attachments for vacuum cleaners. More particularly, this invention relates to a rug cleaning attachment which has a suds confining chamber and a scrubbing brush mounted thereon for rotation about a horizontal axis within the chamber. In one specific aspect, the invention relates to a rug cleaning attachment for use with a vacuum cleaner of the type having a fan casing with a vacuum housing for attaching a vacuum nozzle and a fan shaft that projects through an opening and having a belt receiving portion outside of the fan casing which may normally receive the driving belt of the rotary brush in the vacuum nozzle.
It has long been recognized that effective suction or vacuum cleaning of a rug may be accomplished by a vacuum nozzle having a brush mounted on a horizontal axis so that the brush picks the dirt out of the carpet pile and this dirt is removed by the suction of the cleaner. Cleaning devices which are intended to shampoo or wet clean a rug, however, are customarily provided with one or more brushes that are mounted for rotation about vertical axes. A suitable rug cleaning solution is foamed into the rug in the vicinity of the brushes and is worked into the rug by the brushes. The bristles of those brushes scrub the rug in an orbital manner and, consequently, the dirt is driven downwardly into the pile of the rug and the orbital brush movement causes the carpet pile to form tangled nubs. Thus, the rug appears to be clean, since the dirt has been removed from the upper ends of the filaments of the rug, but, in fact, the dirt has been driven downwardly into the pile. It is very difficult to remove this dirt by later vacuuming because the rug detergent tends to harden and hold the dirt in the pile as a cake. Rug cleaning brushes which are mounted for rotation about vertical axes, moreover, tend to twist the filaments of the rug and also tend to concentrate the nap into small tufts or balls.
Attempts have been made to overcome the deficiencies of the previously described rug cleaners by mounting the cleaning brush for rotation about a horizontal axis. These attempts were not all together successful, since the cleaning suds were not initially confined to the zone of contact between the brush and the rug, and effective means were not provided for the removal of the spent or soiled suds. Thus, while a driven horizontal brush provided a deep cleaning action it inherently created a problem of suds confinement at its working surface and suds disposal and containment since the horizontal brush tends to throw the suds tangentially upwardly while a brush mounted on a vertical axis would tend to throw the suds laterally along the carpet in a less objectionable fashion.
In U.S. Pat. No. 3,370,315 there is disclosed a rug cleaning attachment which successfully overcame many of these prior art problems by providing an attachment which has a suds confining chamber and a brush mounted for rotation about its horizontal axis which could be readily and conveniently operatively engaged and disengaged from the vacuum cleaner without special tools or skills. The rug cleaning attachment according to that patent collects any nap which is removed from the carpeting and which discharges soiled and spent rug cleaning suds into a conveniently accessible chamber. Further according to that prior art patent the spent suds were scraped from the horizontal brush by a doctor blade having a straight blade which engages the rotating suds laden bristles.
While the commercial devices produced according to the aforementioned patent perform their intended purpose and effectively remove soil from rugs, certain operational drawbacks are experienced. As the horizontal brush rotates from its rug scrubbing position to the suds scraping doctor blade, the spent suds on the brush are subjected to centrifugal forces which tend to spray the spent suds in the nozzle chamber. Although the nozzle chamber is vented to minimize direct suction from the carpet to the fan housing, spent suds are inevitably drawn into the fan and motor housing of the vacuum cleaner. Moreover those suds are sprayed onto the driving belt and its drive shaft. Furthermore, the suds which are generated ahead of the brush are laid in a path along the entire extent of the horizontal brush and those suds tend to act as a lubricant between the drive belt and the horizontal brush causing further belt slippage. Also, generated and spent suds tend to foul the end bearings for the horizontal brush.
The doctor blade of the commercial device presents a further operational problem after continued use. After such use the bristle ends of the brush tend to be worn by the straight edged doctor blade and the suds stripping action of the blade is gradually diminished necessitating incremental adjustments of the blade toward the axis of the brush.